The cycling infrastructure in the Netherlands is amazing, and the cyclists in my hometown of Utrecht would be the happiest in the world if it weren’t for one thing: pigeons.
One moment you are pedaling under the sun with a cool breeze on your face, the next moment you are breaking and off the road. A pigeon casually crossed your path, unaware of the danger it was putting itself in. Growing up, I often wondered how stupid they were to swerve blindly into traffic. Years later, I once again find myself pondering pigeon intelligence, but this time in a new paper on collective intelligence and flight paths in the journal PLOS Biology.
While this research generally suggests that my biases may be correct, some details in my new study findings suggest that pigeons may be smarter than I thought.
A few years ago, when I was still unimpressed with pigeon intelligence, I came across a 2017 research paper by biologists Takao Sasaki and Dora Biro. Their study outlined how pigeons fly home when released from a particular area. At first the birds find a somewhat circuitous route. Then, with each successive version, they would remember and reproduce exactly the same path.
However, Sasaki and Biro showed that their new route was slightly more efficient when naive pigeons were paired with more experienced pigeons. For several generations, researchers replaced the most experienced bird in the pair with a naive one. While fixed pairs continued to fly the same (more circuitous) routes over and over again, generational change ensured that each generation got a little closer to the most direct route from A to B.
Some scholars have treated this as an example of cumulative culture. This is a new behavior that is passed on to others through social learning, which improves performance and is repeated over time to create sequential improvements. This last concept is also known as a peg in psychology.
Whether the pigeon’s cumulative culture is the same as ours is hotly debated among scientists. But I was intrigued by these pigeons and their cumulative route improvements and wanted to know how they did it. Sasaki and Biro suggested that birds could aggregate information and evaluate their performance.
I, on the other hand, was wondering if there was a path to cumulative route improvements that didn’t require intelligence. I turned to computer simulation and developed a simplified model of bird navigation. I wanted to create robot pigeons that could demonstrate route improvements without communicating or complex thinking.
The robot pigeon model consists of four components. Pigeons know roughly where their home is using the sun and the Earth’s magnetic field (we know this because people have glued magnets to pigeons’ heads, which prevents them from orientating). They also seem to like to fly together, and aligning their direction of travel is a very important part of flock behavior. The third element was route memory. When pigeons are released from the same location, they fly home in the same way, apparently using landmarks along the route. Finally, flight paths tend to have continuity. This reduces the possibility of sudden sharp turns, which prevents irregular patterns.
Just like Sasaki and Biro did with real pigeons, I let my robot pigeons “fly” alone, in pairs, and with intergenerational alternation. In each generation, the most experienced robot was replaced by a naive robot. Despite being extremely simplified versions of pigeons (without communication or thought), the robots successfully flew from point A to point B, remembered unique paths, and showed cumulative improvements.
The nice thing about computer models is that you can hack them to see how they work. By changing the robots’ settings, I can demonstrate conditions under which couples with generational change generally outperform couples in the control condition (no generations). I can also turn off each of the components to show that goal direction, social proximity, and route memory are required for cumulative route improvements to occur.
The final question was why the pigeons in Sasaki and Biro’s study continued to find more efficient routes. Some of this is obvious. Each new naive robot pigeon can learn a set path from its more experienced counterparts. But this does not explain why the routes evolved. It turns out that naive pigeons actually help experienced pigeons here.
They had no predetermined path to follow, but they knew roughly where the target was. This made them slightly more likely to go off course towards the target, which subtly diverted the new pair’s course to be slightly more efficient.
The study showed that cumulative route improvements can occur across generations in the absence of communication or complex thought. It relies on the pigeons’ rough idea of where the target is, their memory of past paths, and their tendency to stick together.
Does this mean that pigeons are really stupid?
My model produced similar pathways to Sasaki and Biro’s pigeon data, showing that birds can act stupidly. However, the model’s parameter estimates varied widely. It was also slightly different whether pigeons flew on their own, in fixed pairs, or with intergenerational change.
This means that pigeons are not automatons: individual birds behaved in different ways and may even have adapted to the conditions. Although the pigeon’s behavior is generally consistent with the model, it may also be doing clever things that the model does not capture.
An example of this can be found in a 2021 study by engineering scientist Gabriele Valentini and colleagues using data from Sasaki and Biro. It was analyzed who took the “leadership” in naive and experienced pigeon pairs. They found that navigation in pairs was surprisingly democratic, with both naive and experienced pigeons initiating exploration for route improvements.
Even if these new routes sometimes accidentally pass through a bike lane, it certainly seems like it could be some form of intelligence.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Edwin Dalmaijer does not work for, consult, own shares in, or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond his academic duties.